Change-speed transmission



Oct. 26, C. M. OLEARY CHANGE-SPEED TRANSMISSION Original Filed April 29, 1949 5 Sheets-Sheet l OOOOO mvrrml Oct. 26, 1954 C. M. @LE/mv 2,692,516

CHANGE-SPEED TRANSMISSION Original Filed April 29, 1949 5 Sheets-Sheet? @frog/V651,

C. M. OLEARY CHANGE-SPEED TRANSMISSION om.V 26, 1954 5 Sheets-Sheet 5 Original Filed April 29, 1949 Oct. 26, 1954 c. M. o'LEARY 2,692,516

CHANGE-SPEED TRANSMISSION Original Filed April 29, 1949 5 Sheets-Sheet 4 Oct. 26, 1954 c. M. O'LEARY 2,692,516

` CHANGE-SPEED TRANSMISSION l original Filed April 29, 19149v 5 sheets-sheer 5 t I v alc 1 Sa. 2z I 227 l TSLUR2 l DSwR Sh Patented Oct. 26, 1954 UNITED STATES PATENT OFFICE CHANGE-SPEED TRANSMISSION Charles M. GLeary, Los Angeles, Calif.

Continuation of application Serial No. 90,473, April 29, 1949. This application November 28, 1951, Serial No. 258,729

9 Claims. l

This application is a continuation oi my application Serial No. 90,473, filed April 29, 1949, for Change-Speed Transmission, now abandoned, and in part covers subject matter disclosed in applicants Patent No. 2,555,454.

The present invention relates to change-speed transmissions. Although shown in a preferred embodiment especially suitable for use in the operation of well drilling apparatus of the rotary type to aiiord drives of different ratios for the rotary table and hoisting drum of such drilling apparatus, the principles of the invention are readily applicable to transmissions arranged to drive many and various other types of apparatus.

An important object of the invention is to provide an improved multi-speed mechanical transmission of the positive ratio type which is especially useful when employed in conjunction with hydromatic torque converters of the Foettinger type. As pointed out in my Patent No. 2,555,454, the range of torque ratios through which such a Foettinger hydraulic transmission will operate at high eiciency is relatively narrow. Although it gives an. infinite adjustability within such narrow range, which is of course a highly desirable characteristic, the efficiency drops off so rapidly upon either side of such range that where a wider range is desired, it becomes a practical necessity to employ a supplemental transmission, ordinarily of mechanical character. In my aforementioned cepending application, I have disclosed an improved planetary gear transmission for extending the range of operation of such a hydraulic torque converter in a manner particularly adapted for driving the rotary table of a drilling machine, and which takes into account the operating characteristics of such torque converters with respect to eiiiciency range as noted. The transmission disclosed in such application employs only a single planetary gearset and affords two mechanical driving ratios, one of which is a direct drive. The present invention aims to improve upon the transmission disclosed in my aforementioned copending application by aording an increased number of ratios and by providing means adapted to drive a plurality of driven elements, as for example the hoisting drum as well as the rotary table, or two or more slush pumps, which may be operated through diierential driving means in such manner as to decrease the danger of overstressing the parts when high loads are encountered with two driven pumps being operated in compound relation, for example.

Still another object is to provide such'a transmission which affords four forward speed ratios and two reverse speed ratios, yet which employs only a single planetary gearset.

It is also an object of the present invention to provide a mechanical change-speed transmission of the indicated character which affords a plurality of speed ratios vso `related to one another as to take advantage of the eiiiciency characteristics of a Foettinger type hydraulic torque converter employed therewith.

Another object s to rprovide such a transmission which is relatively light in weight and compact in construction in proportion to `its torque handling capacity, which has relatively few operating parts, most of the operating parts of which are enclosed and protected, which is easy to service and maintain, and which readily adapts itself to automatic control mechanisms to permit changes of ratio .to be effected automatically without requiring the attention of an operator, and in accordance with the most efficient operating characteristics of a related hydraulic torque converter, as previously noted.

Other objects and advantages will become apparent upon consideration of the present disclosure in its entirety.

In the drawings:

Figure 1 is a somewhat diagrammatic, horizontal sectional plan view of a transmission constructed in accordance with .the present invention showing the transmission in substantially diametric section and illustrating associated driving and driven elements;

Fig. 2 is a diametric sectional view oi the gear case on a larger scale, showing the principal .gear elements and associated parts;

Figs. 3 and 4 are cross-sectional views taken substantially on the `lines 3-3 and 4--4, respectively, of Fig. 1 and looking in the direction of the arrows, .some parts vbeing `shown diagrammatically; and

Fig. 5 is a schematic wiring diagram.

Referring now to the drawings, reference character -l is applied -to a diagrammatic representation of an internal combustion engine, depicted to -typify a prime mover or other sources of mechanical power, since any suitable power source may be employed without departure from my invention. Internal combustion engines, `arranged either singly or .in 'banks of two or more are commonly employed in oil well drilling operations, for which my improved vtransmission apparatus is well suited. Engine I- drives, through a hydraulic torque 1converter I2 of the Foettinger type and suitable chain 'and sprocket "B J connecting means, generally designated i4, a iackshaft I5. Such parts will be recognized as conventional in the art. Jaekshaft l5 is journaled in suitable bearings as l5 and carries at spaced points thereupon a pair of duid-operable friction clutch assemblies, respectively designated A and B. The details of construction of such clutches are well known in the art and will require no exposition here. Engagement and disengagement of clutch A renders a driving sprocket 26 fast and loose with respect to jackshaft l5. Sprocket 26 drives a transmission input sprocket 3l) through a chain 28. Engagement and disengagement of clutch B renders a driving sprocket 22 fast and lose with respect to jackshaft l5. Sprocket l22 drives a second transmission input sprocket 25 through a chain 24.

The transmission includes concentric driving and driven shafts carried by a case 33 having a supporting pedestal portion 34 by which it may be mounted upon any suitable fixed platform, in such position that the transmission shafts are substantially parallel to and spaced from the jackshaft l5. As best shown in Figs. 3 and 4, the case 33 is essentially cylindrical in form and supports in its left end wall (as the parts are Viewed in Figs. l and 2) a tubular driving shaft 40 journaled in suitable antifrietion bearings as 36, 38 and projecting both into and outwardly from the casing. Input sprocket 25 is fast upon tubular shaft 45 beside the end wall of the case. Tubular input shaft 44 is similarly journaled in the right end of the casing and projects therefrom to carry fast thereupon the input sprocket 30 previously mentioned.

Fast upon the inner end of input shaft i0 within the case is a sun gear 45. Fast upon input shaft All within the case but spaced axially from the sun gear is an internal toothed ring gear d5.

A plurality of double planetary gear assemblies coact with the sun gear 45 and internal toothed ring gear 56. As best shown in Fig. 2, each double planet gear assembly comprises a pair of coaxial, rigidly connected gears 50, 52, journaled on a suitable planetary stub axle as 54. The planetary stub axles form part of a cage or carrier structure generally designated 55. Planet gears 50 mesh with the sun gear 45 and are somewhat smaller than planet gears 52, which mesh with internal gear 4S. A web 56 rigidly connected to and shown as formed integrally with the cage 55 extends radially inwardly between the spaced inner ends of the tubular shaft portions Ml, fill, and is made fast to an axial driven shaft Si] which is freely journaled in the tubular shafts 40, 44, as by means of the antifriction bearings 62, Sil. Driven shaft S extends outwardly through and from the outer ends of both of the tubular shafts liti, 44. A mid portion of axial shaft 50 is enlarged and splined as indicated at to receive the conformably internally splined portion of carrier web 56.

A cylindrical outer peripheral braking surface 66 is formed integrally with the internal gear 46 and lies close to the peripheral wall of the casing 33. A similar braking surface 68 is provided, carried by a web 'I0 secured as by screw means 72 to the sun gear 45. Such cylindrical braking portions are adapted to coact with automatic one-way acting brake means, the construetion of which maycorrespond substantially to the analogous parts of my Patent No. 2,555,454, previously mentioned. Each such brake includes a plurality of wedge blocks at l5, Fig. 3,

urged to a wedging position by a helical compression spring but normally held out of wedging position by an opposed compression spring 82 which is strong enough to overcome spring l5. Three such blocks are shown but description of one will sufce. When the block 'i5 is free to move to the wedging position under the influence of the spring TB, it is effective to prevent reverse rotation of the drum and so of the gear connected thereto. The drum is nor- Ina-,ily reversible, however, because vthe wedge is held in an inoperative position by a retracting device comprising a finger as 'I8 attached to and movable by a piston 89 against which spring 62 acts to overcome the effect of spring i6. Spring 8?. is housed in the cylinder il which contains the piston 8B and acts in a direction to move the finger i8 against the smaller' end of the wedge-shaped block l5 and so drive the latter toward the larger end of its wedge-shaped enclosure 85 to free the block from braking engagement with the drum. As best shown in Fig. 3, the housing portion 85 and all parts of the one-way brake structure may be carried by an integral extension of the case 33. The one-way braking means for the internal gear t5 and the actuating means therefor are grouped under the general designation G. When fluid under pressure is admitted to the cylinders @Il through couplings as 8G at the outer ends theres the effort of their respective springs E32 is overcome and such springs are compressed as fingers l2 move away from wedges 'i5 to allow the latter to move to wedging position under the influence of the springs lt. Although in the structural arrangement shown in this application the brake blocks l5 are so arranged as to be normally held out of engagement by the springs 32, it will be recognized that if preferred the blocks could be of the type which is normally urged into engagement with the drum, and moved away from the drum by fluid pressure, rather than moved into engagement with the drum when duid is supplied to their actuating means. In the construction shown in my Patent No. 2,555,454 previously referred to, the one-way brake blocks are normally allowed to drag, and are only disengaged during reverse operation. Such dragging has been eliminated in the present construction, in order to reduce the generation of heat, but it will be recognized that except for this factor, the operation is essentially the same. If the brake blocks were of the dragging type of my copending application in question, the blocks would drag during second and fourth speed operation, would engage automatically in first speed and in third speed, and would be positively released during reverse operation.

The one-way brake means for the sun gear 45 may consist of a plurality of wedge-shaped one-way brake blocks 90, the mounting and mode of actuation of which may correspond to those of the brake blocks 'l5 just described. Such oneway brake and the actuating means therefor is grouped under the general designation. H. and is also arranged so that the blocks are rendered operative when fluid such as air under pressure is delivered to the actuating means. It will again be recognized that brake blocks of the dragging type, equipped with fiuid-actuatable disengaging means, could be provided in lieu of the normally disengaged blocks, and that the operation would remain essentially the same, as previously pointed out.

The planet carrier 55 is also provided with a peripheral cylindrical braking surface portion 02 with which a friction brake band y54 is adapted vto coact to immobilize the carrier :at desired times. As best shown in Fig. 4, brake band 04 is .adapted to be applied by means of a hydraulic piston .and cylinder assembly, and this `brake and its applying means are generally designated J. The .applying means comprises a cylinder 95 lcarried by the housing 33 and containing a piston 9B to which a rod 98 is secured, the other end of the rod being attached to an end of the band 94. A spring within the cylinder and acting against the piston 96 tends to release the band, which is applicable when iiuid under pressure is introduced into the end of the cylinder opposite to that which contains the spring, the fluid being admissible through a suitable hydraulic coupling |02. The specic design and arrangement of the planetary gearing described above are claimed in my Patent No. 2,555,454.

The left-hand extremities of the intertted shaft portions 40, 00 (as the parts are Viewed in Fig, 1) project into a drivable clutch drum assembly generally designated |05, consisting of -a hollow cylindrical casing assembly concentric with the shafts and which also constitutes the driven element of both of the two clutch structures housed therein. Hollow shaft 40 carries fast upon its extremity within the cylindrical casing |05 a cylindrical clutch driving drum element |05. Shaft 60 projects beyond the free end of hollow shaft 40 to carry a similar cylindrical clutch driving drum element |08 fast thereupon. Drum |05 supports an antifriction bearing assembly i i0 for the outer end of shaft 50 and also a lubricant retainer H2. The clutching means contained in the drum |05 is similar to the clutching means disclosed in my aforementioned Patent No. 2,555,454, and consists of means for selectively clutching the driven drum |05 to either of the driving drums |05, |03., or for clutching all three such parts together, as may be desired.

A clutch band portion I I5 is radially inwardly movable to engage the periphery of driving drum |05` when urged inwardly there against in response to the distention of a hollow annular flexible tube H5 of rubber or the like. The relaxed contour of tube ||5 is substantially that of a radially flattened hollow torus, to the interior of which suitable fluid pressure may be applied as through a supply conduit l |B. The clutch applying means consisting of tube llt` and associated parts is generally designated D. A similar peripheral clutch applying tube |20 is adapted to be distended radially inwardly by fluid delivered thereto through a conduit |22 to cause a clutching element 24 to clamp the periphery of driving drum |08 in analogous fashion. This clutch and its applying means consisting of tube |20 and associated parts is generally designated C. The bands M5 and |24 are held against rotating with respect to drum |05 by suitable keying means as Driven drum |05 is carried by a hub portion |25 journaled in xedly mounted antifriction bearing means |26, |28. The conduits H8, |22 rotate with the drum |05 and could of course be formed as internal passages in the drum if preferred. Such conduits communicate with passages |23 and |2l, respectively, which extend longitudinally through the hub |25. A manifold assembly |20 at the outer end of the hub |25 communicates with the passages |23, |2l lto provide a continuous fluid conductive running connect'ion between :passage l|23 and a fluid suppl-y' Driven sprocket 434 is carried by a jackshaft |v and fast with respect to a sprocket |60 from which a ldrive `may be `conducted by a chain |82, to a driven part such, for example, as the rotary table of a drilling rig.

At the right-hand end of the assembly, as the parts are viewed in Fig. 2, tubular shaft 44 and the axial shaft 60 project into a driven clutch housing v.drum |40. The right-hand driven drum |40 corresponds in lconstruction and arrangement to the rleft-hand drum |05 previously described, and equivalent fluid-actuatable clutching means are provided for selectively making and breaking driving connections between the ydrum |40 .and the shafts 44 ,00. Ilfubular shaft 44 carries fast upon its end within .the driven drum 40a clutchdriving drum |42, whilespindle carries a similar clutch-.driving drum |44. Brake bands |45, |45, respectively, are arranged to coact with the driving drum :portions |42, |44, being selectively movable into operative yengagement therewith by distensible tubes as |48, |50, the arrangement and mode of actuation of which may correspond to those of the .tubes I6, |20 .previously described. Actuating uid is delivered to tube |48 through a conduit |52., while actuating fluid is delivered to the tube |50 through asimilar conduit |54, these parts rotating ywith the drum |40 and being connected to internal uid delivery passages |55, |55, respectively, in the hub portion |50 which carries the drum |40. A manifold .provides a running huid-right connection between passage |55 and a fluid supply conduit |52 and between passage |55 and a uid supply conduit |64. The right-hand clutch, actuating tube |50 and associated 4parts are grouped under the general designation E, while the other clutch with its actuating means `consisting of tube |48 and associated parts is generally designated F.

An output sprocket fast upon the hub portion |58 of the driven drum |40 is adapted to be connected as by the chain |56 to the driving sprocket l0 of the hoisting drum |l'2.

Driving sprocket 22 is preferably made twice the diameter of the driven sprocket 25, while driving sprocket 25 is half the diameter of driven sprocket 30. The speed ratio of jackshaft i5 with respect to the tubular input shaft 40 is therefore 1-to-2-; while the speed ratio of the driving jackshaft |5 with vrespect to tubular input shaft 44 is 2-to-1. These values are chosen out of consideration for the operating characteristics of the Foettinger-type hydraulic torque converter, previously referred to. For similar reasons, the transmission gears are so selected that coacting with the sprocket means each speed change doubles or halves the speed ratio. It will be appreciated that in this manner the hydraulic torque converter can be kept operating within its range of highest efficiency. In the preferred embodiment depicted, for example, the diameter of the sun gear 45 is 20 inches, the diameter of the internal toothed Aring gear 46 is 30 inches, the diameter of the smaller Agear of yeach planetary cluster is 4 inches, and the diameter of the larger gear of each planetary cluster is 6 inches.

With the parts arranged in the manner de- :i scribed, input to output speed ratios of ll-to-l,

2-to-1, l-to-l, and l-to-2 are available in a forward direction. A low speed drive to the output sprocket |36 for the drilling table is effected by engaging clutches A and C and one-way brake means H. Internal gear 4S then rolls the planetary gears upon the sun gear 45, carrying the cage 56 forwardly at areduced rate of speed. Shaft 60 is accordingly turned at the equivalent speed and the drive is transmitted to the drum |05 through the clutch members |53, |24. It will be seen that by selectively engaging and disengaging the clutch band |45 of clutch E, the same reduced speed drive may be taken from the opposite end of the transmission, for operating the hoisting drum H2. The second speed drive to the table drive output sprocket |35, at the 2-to-l ratio, is also taken through the clutch A and sprockets 26, 3Q, and tubular shaft 44. Both clutches C and D are engaged with their respective drums |42, I 44 and the planetary gearing is accordingly locked up so that both shafts and the drum |85 are driven at the same rate as the hollow spindle 44. The same drive is available at the other end of the transmission by engaging either or both of the clutches E, F, as will be apparent.

A third speed drive at the ratio of l-to-l is made available by disengaging clutch A and engaging clutches B and C and one-way brake G. Hollow input spindle 45| is thereby rotated at twice the speed of the driving jackshaft I5 and the planet gears are rolled on the internal toothed gear 45, reverse rotation of the ring gear being prevented by the one-way brake blocks 15. The planet carrier is thereby turned forwardly at half the speed of the input shaft and such drive can be taken from either end of the transmission by engaging either or both of the clutches C and E.

When the high speed drive is desired at the left end of the transmission, it is only necessary to engage clutches B, C and D to drive the drum |55 and sprocket |36 at the speed of the input shaft 4G. When this higher speed drive is desired at the right end of the transmission, both of the clutches E and F are engaged concurrently with clutch B, so that the gearing is locked up and the spindles 44, |50 and output sprocket |55 are also driven at the same rate as the input spindle 40.

A reverse drive to the left or turntable sprocket I 39 is effected by engaging the brake J to hold the carrier, while simultaneously engaging the clutch A. The planetary gear clusters are accordingly rotated upon their individual stub axles to impart a reverse drive at reduced speed to the sun gear 45. Spindle 4G is thereby turned backwards, and the drive to the sprocket |33 is completed by engaging the clutch D. It will be noted that under these circumstances tubular shaft 44 acts as the planetary output shaft.

A reverse drive to the right or drum output sprocket |55 is derived by engaging clutches B and F and brake J. The planetary gear clusters are accordingly turned upon their individual axes to rotate the internal gear 4E, hollow spindle 44 and drum |46 backward. In this case tubular shaft 44 acts as the planetary output shaft. It will be appreciated that this reverse drive is at a higher speed ratio than the reverse drive previoosly mentioned for the other output sprocket |38, but that if it is desired to provide two reverse speeds at both ends of the transmission, this may of course be done by suitable supplemental shafting, or the reverse speed ratios may be changed by reversing the arrangement of the driving sprockets 22, 25 and 25, 30.

All of the four forward speeds previously described are inherently capable of providing positive simultaneous drives to both of the two output sprockets |30, |65. It is also possible to drive the two output sprockets simultaneously but differentially, in such manner as to equalize the torque delivered to the two output sprockets. This is of great advantage under some conditions, as for example if the two output sprockets are employed to drive compounded slush pumps. In compound slush pump operation, it frequently happens that due to an obstruction the power demand of one pump increases greatly with respect to the other. With positive drive, the obstructed pump may absorb the entire torque output and damage may result, although if under such conditions the drive could be transferred primarily to the unobstructed pump, and the latter speeded up, it would help to clear the obstructed pump. With my improved transmission used as a differential drive under such conditions, the more heavily loaded pump will slow down, and the unobstructed pump will speed up proportionately until the loads are again equalized. This greatly reduces the danger of overstressing any of the parts of either pump.

One such differential drive is derivable by simultaneously engaging clutches A, E and D. This constitutes a low speed differential drive, due to the relative sizes of the sprockets 26 and 30. This drive applies torque in a forward direction to the sprocket because the carrier 55, to which sprocket is connected through clutch E, is urged forwardly as the planetary gears are rolled forwardly over the sun gear 45. The reaction of the planetary gears upon the sun gear applies reverse torque to the sun gear and through shaft 40, and clutch D transmits such reverse torque to the other sprocket |30. Torque is accordingly applied to the sprockets |39, |55 in opposite directions, but where the sprockets are employed to drive pumps, the direction of rotation is immaterial since it may be compensated for by the manner of connecting pumps, as will be understood.

A higher speed differential drive is derivable in a similar manner by simultaneously engaging the clutches B, C and F. Forward torque is now applied to the carrier 55, and through shaft 6D and clutch C to the sprocket |30, while reverse torque is applied through the planetary gears and internal toothed gear 45, shaft 44 and clutch F to the sprocket |65.

In Fig. 5, l have schematically indicated a suitable wiring arrangement adapted to provide manually controllable push button operation for changing the speed ratios of the transmission. Referring to Fig. 4, it may be assumed that each of the fluid-operable actuating means for the several clutches and braking devices includes a solenoid-operable three-way valve corresponding to the one shown in that View and comprising a body portion 260 to which fluid under pressure, which may comprise air, may be delivered through a conduit as 252. The details of such valves are well known in the art and need not be considered herein. The valve is movable under the control of a solenoid Sh to either of two positions, in one of which it establishes communication between the supply conduit 202 and a conduit 205, while in the other position the conduit 2132 is cut oi and conduit 202 is placed in communication with a vent 25S. The conduit 206 is connected to .the fluid actuating means for the several one-way braking devices, designated H, for the sun gear 45.

Fig. 4 also shows a conduit 2li) extending to the cylinder for the reverse reaction brake actuator J, and it will be understood that a similar solenoid-operated valve is incorporated between the source of fluid supply pressure and the conduit 2 I6, and that one'such solenoid-operated valve is provided for each of the other` brake clutch actuating mechanisms, as previously indicated. The solenoids for all such valves are diagrammatically shown in Fig. 5, where the several solenoids are designated Sa, Sb, Sc, Sd, Se, Si', Sg', Sh and Si'. The second letter of each such designation corresponds to the previously indicated alphabetical' designations appliedl to the several' brakes and clutches. Each such solenoid has one lead line connected to a power supply conductor 220'. In the arrangement shown in Fig. 5, one electrical switching device is provided' for each forward speed for each end of the transmission, and one switching device for each reverse speed, although this arrangement is of cou-rsegiven by way of example and subject to variation. Button-type contactors are shown in the drawing, but it will be recognized that this is also al matter of choice. Preferably also a conventional interlock system is provided to prevent the closing of more than one switch at a time, or tov prevent the simultaneous closing of switchescorresponding to twol different speeds at the same. time.`

Each of the several buttons is arranged/tocomplete an electrical connection between the power lines 220, 222 and such solenoids as require actuation in order to establish one speed ratio. The switch buttons for the left or table driving` end of the transmission are arranged one under the other and successively designated TSwl, TSwZ, TSw3, TSwll and TSwR. The switch buttons for the right or drum end are similarly designated DSwl, DSwZ, DSw3, DSwfl and DSwR. It isbelieved that a detailed tracing of the wires connected' to the several switches will not be required. It` will be noted that TSwI, when closed, completes a connection from conductor 224 to the conductors 225, 226 and 22T, which lead' respectively to the solenoids Sa, Scand Sh. These solenoids cause engagement of clutches A and C and one-way brake H, respectively, and as previously pointed' out, the simultaneous engagement of clutches A and C and' one-way'brake H is effective to impart a low speed drive to sprocket 1'30. Similarly, thev closingk of TSwZA completes' a' connection from power supply conductor 222r to the solenoids Sa, Sc and Sd for clutches A, C and D, comprising' the' second speed table drive group; the closing of '1`Sw34 completes aconnection to solenoids Sb, Sc and Sg for clutches B and C and one-way brake G, constituting the third speed table drive group; the closingv of TSwll" completes a connection to solenoids Sb and Sd for clutches B and D, comprising the fourth speed table drive group; and the closing of TSwR. completes a connection to the solenoids Sa, Sd and S7' for clutches A and D and reaction brake J', for low speed reverse operation of table drive sprocket |30.

The closing of DSwl completes a connection to the solenoids Sa, Sel and Sh to engage clutches A and-E and one-way brake H for rst speed operation of the drum or right-hand output sprocket |65. The closing of DSw2 completes a power connection to the solenoids Sa and Sf tol engage clutches A and F of the second speedk drum drive group; they closing of DSwS completes a connection to the solenoids Sb, Sc and Sgv for clutches B and E and one-way brake G, comprising the third speed drum drive group; the closing of DSulcompletes a connectionV to the solenoids Sb, Se'andf SJ for clutches B, Eand F, comprising the fourth speed drum drive group; andI the closing 10 of DSwR completes a connection to the solenoids Sb, Sf and S7' for clutches B andv F and reaction brake J, comprising the higher speed reverse drive group for drum sprocket H55. As shown, these switches are arranged so that when each switch is open, it breaks all connections through that switch to the several solenoids. It will be understood that any other suitable wiring or control arrangement may be employed', and that if preferred, automatic actuation could be provided, as for example, in the manner disclosed in the copending application of John` A. Blair, Serial No. 675,821, filed May 18, 1946, now Patent No. 2,529,129. Such automatic operation, coi-dance with the disclosure of the Blair application referred to, could readily be effected by arranging for each of the forward= speedl switches TSwl, TSw2, 'ISw3` and TSwil and DSwi, DSwZ, DSwS and DSall to be actuable to the closed position by a solenoid analogous to the ,K that only one such solenoid would be energized at 30 al time in accordance with the modified arrangement described on page 23v of the Blair application, lines 1-15, inclusive.

Another typical alternative wiring arrangement would be one employing switches adapted to simultaneously energize the valve actuating solenoids Sa, Sd and Se for a lowl speed differential drive to both ends of the transmission simultaneously and/or to simultaneously energize the solenoids Sb, Sc and Si forahigher speed differential drive, as also previously explained.

While it will be apparent that the preferred embodiment of the invention herein disclosed is well calculated tofulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined` claims. mechanisms incorporating certain of the broad features of that described herein are disclosed' and claimed in applicants copending applications, Serial No. 647,677, filed February 15, 1946,

now Patent No. 2,589,119; Serial No. 676,450, led4 June 13, 1946, now Patent No. 2,589,121; and Serial No. 746,664, led May 8, 1947', now Patent No. 2,588,408.

What is claimed is:

1. A planetary transmission construction comprising a pair of longitudinally spaced but axially aligned tubular input shafts, a planetary gearset including a pair of coaxial gears one drivable by each of said input shafts, planetary gear means interconnecting said coaxial gears, a carrier rotatably supporting said planetary gear means,v

an axial output spindle extending through said tubular input shafts and projecting at both ends r from said tubular shafts and connected to said 75 prising a pairrof longitudinally spacedv but axially in ac- Transmission aligned tubular input shafts, a planetary gearset including a pair of coaxial gears one drivable by each of said input shafts, planetary gea-r means interconnecting said coaxial gears, a carrier rotatably supporting said planetary gear means, an axial output spindle extending through said tubular input shafts and connected to said carrier, means for driving said tubular input shafts at different speed ratios, separate selectively operable means for preventing rotation of each of said coaxial gears, a fixed housing enclosing the abutting ends of said tubular input shafts and also enclosing said gears and carrier, said housing also rotatably supporting said shafts and said output spindle and gears, said spindle projecting at each end beyond the tubular shafts, the two tubular shafts and the two ends of the output spindle projecting laterally from opposite ends of said fixed housing, a driven clutch drum at each end of the transmission, each such drum enclosing one end of the spindle and the projecting end of one of said tubular shafts, and clutch means within each drum for selectively completing an output connection to either the spindle or shaft or to both the spindle and shaft simultaneously.

3. A power transmission system including a planetary transmission having three interconnected gear elements, two tubular shafts in substantially coaxial relation, each tubular shaft being connected to one of said elements, and an axial shaft rotatable in said tubular shafts and connected to the other of said elements, said tubular shafts being arranged end-to-end and said axial shaft extends through both tubular shafts, a central casing enclosing the inner abutting ends of said tubular shafts and rotatably supporting the same, said casing also enclosing said gear elements, two toothed driving members of different sizes each carried by one of said tubular shafts and one arranged on each side of said casing, said casing being fixed against rotation, reaction means carried by the casing for preventing unwanted rotation of certain of said gear elements, a pair of power output shafts axially aligned with said axial shaft at opposite ends of the latter, and a clutch means associated with each output shaft for selectively clutching the same to said axial shaft or the adjacent tubular shaft or both said last Vmentioned shafts.

4. A power transmission system including a planetary transmission having three interconnected gear elements, two tubular shafts in substantially coaxial relation, each tubular shaft being connected to one of said elements, and an axial shaft rotatable in said tubular shafts and connected to the other of said elements, said tubular shafts being arranged end-to-end and said axial shaft extending through both tubular shafts, a driving shaft, means for selectively driving said tubular shafts at different speed ratios from said driving shaft, reaction means for preventing unwanted rotation of certain of said gear elements, a pair of power output shafts axially aligned with said axial shaft at opposite ends of the latter, and a clutch means associated with each output shaft for selectively clutching the same to said axial shaft or the adjacent tubularI shaft or both said last mentioned shafts,

5. In combination, a hoisting drum and rotary table drive shaft assembly having coaxial toothed driving elements at opposite ends of the drum, one of said elements being connected to the drum and the other being connected to the rotary table drive shaft, a pair of spaced coaxial shafts extending parallel to the axis of the drum and having toothed driving elements operatively connected respectively to said driving elements, an intermediate shaft coaxial with and between said spaced shafts, a pair of axially spaced tubular shafts surrounding said intermediate shaft, clutch means associated with each of said rstmentioned spaced shafts for selectively clutching the same to the intermediate shaft or the adjacent tubular shaft or to both of said lastmentioned shafts, a planetary transmission having three interconnected gear elements connected respectively to said intermediate shaft and said tubular shafts, means for preventing unwanted rotation of said tubular shafts, a power supply shaft, and means for selectively driving said tubular shafts from said power supply shaft at different speed ratios.

6. In combination, a hoisting drum and rotary table drive shaft assembly having coaxial toothed driving elements at opposite ends of the drum, one of said elements being connected to the drum and the other being connected to the rotary table drive shaft, a pair of spaced coaxial shafts extending parallel to the axis of the drum and having toothed driving elements operatively connected respectively to said driving elements, an intermediate shaft coaxial with and between said spaced shafts, a pair of axially spaced tubular shafts surrounding said intermediate shaft, clutch means associated with each of said first-mentioned spaced shafts for selectively clutching the same to the intermediate shaft or the adjacent tubular shaft or to both of said last-mentioned shafts, a planetary transmission having three interconnected gear elements connected respectively to said intermediate shaft and said tubular shafts, means for preventing unwanted rotation of said tubular shafts, means for holding said intermediate shaft against rotation, a power supply shaft and means for selectively driving said tubular shafts from said power supply shaft at different speed ratios.

'7. A power transmission system, including a planetary transmission having three interconnected gear elements, a pair of shafts having a common axial line connected respectively to two of said elements, a third shaft having the same axial line as said pair of shafts and connected to the other of said elements, selectively operable means for driving either of said pair of shafts at different speed ratios from a common power source, means operable to prevent relative movement between the elements of said planetary transmission, and separate selectively operable means for holding either of said pair of shafts stationary.

8. A power transmission system, including a planetary transmission having three interconnected gear elements, a pair of shafts having a common axial line connected respectively to two of said elements, a third shaft having the same axial line as said pair of shafts and connected to the other of said elements, selectively operable means for driving either of said pair of shafts at different speed ratios from a common power source, separate selectively operable means for holding either of said pair of shafts stationary, and clutch means for selectively completing an output connection to either said third shaft or one of said pair of shafts or to both said third third shaft and one of said pair of shafts simultaneously.

9. A power transmission system, including a planetary transmission having three interconnected gear elements, a pair of shafts having a common axial line connected respectively to two of said elements, one of said pair of shafts being tubular, a spindle extending through said tubular shaft and connected to the other of said elements, selectively operable means for driving either of said pair of shafts at different speed ratios from a common power source, separate selectively operable means for holding either of said pair of shafts stationary, a power take-olf shaft, and clutch means associated with said power takeoff shaft for selectively clutching said power takeoff shaft to said spindle or said tubular shaft or both said spindle and said tubular shaft simultaneously.

References Cited in the file of this patent UNITED STATES PATENTS Number Number 14 Name Date Dresser Nov. 17, 1903 Rowledge Feb. 12, 1918 Fawick Sept. 10, 1940 Schmitter Dec. 1, 1942 Coy Nov. 9, 1943 Orr Jan. 2, 1945 Kelbel June 18, 1946 Winthers May 27, 1951 OLeary June 5, 1951 OLeary Apr. 22, 1952 

